The present invention relates to a coal dust combustion motor with a piston reciprocatable in a cylinder and with a whirling or precombustion chamber communicating with one end of the cylinder, into which a mixture of air and coal dust can be blown under pressure.
Coal dust combustion motors are known in the art in which during the suction stroke of the piston in the cylinder coal dust is sucked due to underpressure in the cylinder space above the piston, controlled by a suitable valve, into a precombustion chamber communicating with the main combustion space. This coal dust should then in these known motors during the following compressing stroke, before it passes into the main combustion space, first be pressed back into the precombustion chamber to be, after reaching the precombustion chamber, combusted and, due to the thereby resulting pressure increase, be blown already burning into the main combustion space. All motors constructed according to this system require for their function thermically unfavorable bottle-shaped precombustion chambers which nevertheless could not prevent penetration of coal dust into the cylinder space before the coal dust was ignited. This resulted in an undesirable increase of wear, since the coal dust which penetrated before its combustion into the main combustion space penetrated between the outer periphery of the piston and the inner periphery of the cylinder. Furthermore, partly combusted dust particles passed from the precombustion chamber coked onto the oil wetted peripheral surface of the cylinder together with ash particles which led to a further abrasive wear. In addition, in these known coal dust combustion motors, it was impossible to influence the moment of combustion in accordance with the respective loading of the motor and the resulting state of heating thereof, and it was also impossible to obtain an elastic regulation of the motor speed and its output. These precombustion motors were connected for stationary operation with considerable disadvantage and for operation in vehicles totally unusable.
A coal dust combustion motor is further known in which the coal dust is blown into the cylinder space at a high pressure of about 70 bar. The therefor necessary expenditure is considerable and results in a higher motor weight, so that such motors may be used in ships or stationary power installations, but they are unsuitable for use in vehicles.
Advantageous is, however, the blowing of the coal dust air mixture into a precombustion or whirling chamber constantly communicating with the cylinder space at a moment during the compression stroke of the piston but before the desired moment of ignition when a gas stream is present leading from the cylinder to the combustion space through which an accumulation of dirt particles on the cylinder wall already before start of the ignition during a larger part of the compression stroke is positively prevented.